When a component is incorporated in a resin multilayer substrate, it is general to use a method comprising: mounting a component on the surface of a resin sheet of a plurality of stacked resin sheets; stacking one or more resin sheets each provided with a through hole in which the component is received; and further stacking an upper resin sheet so as to cover the component disposed within the through hole.
Also, there is a proposed method comprising: forming a cavity by creating a through hole in each of some resin sheets of a plurality of stacked resin sheets; inserting, into the cavity, a corresponding one of components separately held by a known technique such as vacuum suction; and further stacking an upper resin sheet so as to cover the component received in the cavity. In this case, if the cavity is equal in size to the component as seen in plan view, the component cannot be fitted in the cavity when the position of the component is only slightly displaced. Accordingly, in order to avoid such a situation, the cavity is formed to have a size larger than the size of the component. Therefore, in the state where the component is placed in the cavity, a gap is produced between the outer circumferential side surface of the component and the inner circumferential side surface of the cavity.
For example, Japanese Patent Laying-Open No. 2008-141007 (PTD 1) discloses a method of manufacturing a multilayer substrate in which an electronic component is embedded in a stack of a plurality of resin films each made of a thermoplastic resin. According to PTD 1, some of the resin films each are provided with a through hole through which an electronic component is inserted. This through hole is formed larger than the outer shape of the electronic component in order to allow easy insertion of the electronic component. PTD 1 discloses that the gap between the outer circumferential side surface of the component and the inner wall of the through hole is filled by a resin flowing thereinto during the process of heating and pressurizing a stacked body.
In the case where such a gap is provided, positioning of the component within the cavity causes a problem. In order to deal with this problem, Japanese Patent Laying-Open No. 2006-73763 (PTD 2) discloses a configuration in which a protrusion is provided in an inner wall of a through hole in order to suppress the positional displacement of a chip component in a manufacturing stage. When a chip component is placed within a cavity, the component is to be press-fitted while it crushes the tip end of each protrusion. In this way, the chip component is supported by this protrusion from the side and thereby positioned within the cavity.